Using data from 1974 to 1977 National Opinion Research Center Surveys, the investigator examined differentials in income between currently employed white men and women aged 25 to 64 (sample size: 965 men and 672 women). Special attention was given to explanatory effects of occupational characteristics other than those traditionally used in the prestige or status-defined model. The results, based on a multivariate regression analysis and a regression standardization procedure, suggest that a significant part of the income gap between men and women is because of the concentration of women in a few occupations which are typically low paying and heavily female and which do not allow their incumbents the opportunity to exercise authority or to control the means of production. Incorporating these factors into a model of earnings hypothetically increased women's earnings as a percentage of men by approximately seven percent, to approximately sixty-three percent. A similar hypothetical improvement was found when just single women's earnings were adjusted to take account of their concentration in low level employment. The addition of occupational characteristics to the income attainment model thus complemented the human capital approach to the male-female earnings differential and improved on the prestige or status-defined model traditionally employed. The findings suggest that male and female workers face a segregated labor market which adversely affects women's earnings relative to men's. (Author/LMS)